1. Field of the Invention
The present invention relates to a library apparatus for storing a plurality of storage media such as magnetic tapes and magneto-optical disks to perform at least information reproduction for those storage media.
2. Description of the Related Art
Hitherto, there is known a library apparatus in which a plurality of storage media such as magnetic tapes and magneto-optical disks is stored, and upon receipt of an instruction from an operator and another apparatus, a desired storage medium is mounted on a drive to record information onto the storage medium and to perform information reproduction for the storage medium. The library apparatus is a so-called back-up apparatus for saving information, providing against an emergency, in such a manner that for example, in a computer network, the library apparatus is connected to a host computer taking a leading part in a plurality of computer systems, the same information as that stored in the host computer is kept.
FIG. 17 is a perspective view of the conventional library apparatus, looking from the front.
A library apparatus 800 shown in FIG. 17 comprises a cover member 810 and a moving mechanism 820 having a horizontal rail 821 fixed on a bottom plate 810a inside the cover member 810 in a horizontal direction.
FIG. 18 is a perspective view of the moving mechanism shown in FIG. 17.
The moving mechanism 820 shown in FIG. 18 comprises: the horizontal rail 821 shown also in FIG. 17; a horizontal direction moving base 822 travelling along the horizontal rail 821 in a horizontal direction; a moving base driving motor 823 fixed on the horizontal direction moving base 822 for moving the horizontal direction moving base 822 in a horizontal direction; a vertical rail 824 fixed on the horizontal direction moving base 822 travelling together with the horizontal direction moving base 822 in a horizontal direction; a storage medium exchanging mechanism 825 travelling along the vertical rail 824 for deriving a desired storage medium from among the stored storage media (not illustrated) to mount the derived storage medium on a drive (not illustrated); and a storage medium exchanging mechanism driving motor 826 fixed on the horizontal direction moving base 822 for moving the storage medium exchanging mechanism 825 in a vertical direction.
Recently as computers have come into wide use, a large amount of information is dealt with routinely, and an amount of information stored in a computer system expands. Thus, there is increased a demand of a library apparatus capable of increasing the maximum storage capacity of the library apparatus serving as a back-up for information.
Hitherto, it is performed that the maximum storage capacity of a library apparatus is increased in such a manner that a plurality of library apparatuses is coupled to one another, and the coupled library apparatuses in its entirety (hereinafter, the coupled library apparatuses in its entirety are referred to as an expanded library apparatus) are regarded as one library apparatus and be used (cf. Japanese Patent Publication TokuKai. 1999-96628).
As types of the expanded library apparatus, there are known types, which will be explained hereinafter.
FIG. 19 is an explanatory view useful for understanding a first type of extended library apparatus of the conventional extended library apparatuses.
The first type of extended library apparatus shown in FIG. 19 is a library apparatus having the same structure as the library apparatus proposed in the referenced above Japanese Patent Publication TokuKai. 1999-96628. The first type of extended library apparatus is equivalent to one in which the library apparatus 800 having the same moving mechanism 820 as the moving mechanism 820 shown in FIG. 17 and FIG. 18 is combined with an extended library apparatus 800′. The horizontal rail 821 provided on the moving mechanism 820 is fixed on a bottom plate inside the cover member 810 in a horizontal direction. Inside the cover member 810, there are provided storage medium storage shelves 151 for storing therein a plurality of storage media 31. The extended library apparatus 800′ is provided with a horizontal rail 821′ fixed on a bottom plate inside a cover member 810′ of the extended library apparatus 800′ in a horizontal direction and storage medium storage shelves 151 for storing therein a plurality of storage media 31.
FIG. 20 is a flowchart useful for understanding a flow in which storage media are carried in the first type of extended library apparatus shown in FIG. 19.
First, there is derived a storage medium 31 stored in a storage medium storage shelf 151 provided in the cover member 810′ of the extending library apparatus 800′ (step S31).
Next, the storage medium 31 derived in the step S31 is carried in the cover member 810′ of the extended library apparatus 800′ and the cover member 810 of the library apparatus 800 (step S32).
Lastly, the storage medium 31 carried in the step S32 is inserted into a recording and reproduction apparatus (not illustrated) provided in the cover member 810 of the library apparatus 800 (step S33).
However, according to the first type of extended library apparatus shown in FIG. 19, when a plurality of library apparatuses is coupled to one another, there is a need to couple horizontal rails to one another, which are fixed on the bottom plates inside the cover members of the plurality of library apparatuses in the horizontal direction, respectively. As mentioned above, the storage medium exchanging mechanism travels along the vertical rail in the vertical direction together with the vertical rail travelling together with the horizontal direction moving base 822 in the horizontal direction. Thus, occurrence of a difference in level on the coupling portion of the horizontal rail makes it difficult that the storage medium exchanging mechanism smoothly travels, and in some case it would be impossible that the storage medium exchanging mechanism travels. Therefore, in some case of conditions of a set up surface for such a type of extended library apparatus, it is difficult to couple a plurality of library apparatuses to one another in such a manner that the coupling portion of the horizontal rail is coupled free from a difference in level, and it will require a great deal of time and labor to establish the extended library apparatus.
FIG. 21 is an explanatory view useful for understanding a second type of extended library apparatus of the conventional extended library apparatuses.
The second type of extended library apparatus shown in FIG. 21 is one in which two library apparatuses each having the same moving mechanism 820 as the moving mechanism 820 shown in FIG. 17 and FIG. 18 are coupled with each other. The horizontal rail 821 provided on the moving mechanism 820 is fixed on a bottom plate inside the cover member 810 of the library apparatus 800 in a horizontal direction. Inside the cover member 810, there are provided storage medium storage shelves 151 for storing therein a plurality of storage media 31. A coupling portion of the cover members 810 of two library apparatuses 800 is provided with a storage medium delivery mechanism 900 in which charging and discharging slot (not illustrated) for inputting or discharging storage media 31 is provided directed toward the inside direction of the cover member 810.
FIG. 22 is a flowchart useful for understanding a flow in which storage media are carried in the second type of extended library apparatus shown in FIG. 21.
In the explanation of the flowchart shown in FIG. 22, of two library apparatuses 800 shown in FIG. 21, the cover member 810 of a right side of library apparatus 800 is referred to as an R side cover member, and the cover member 810 of a left side of library apparatus 800 is referred to as an L side cover member.
First there is derived a storage medium 31 stored in a storage medium storage shelf 151 provided in the R side cover member (step S41).
Next, the storage medium 31 derived in the step S41 is conveyed in the R side cover member (step S42).
Next, the storage medium 31 conveyed in the step S42 is inserted from the charging and discharging slot into the storage medium delivery mechanism 900 (step S43).
Next, in the storage medium delivery mechanism 900 into which the storage medium 31 inserted in the step S43, the inserted storage medium 31 is transferred to the L side cover member side (step S44).
Next, the storage medium 31, which is transferred to the L side cover member side in the step S44, is delivered from the charging and discharging slot of the storage medium delivery mechanism 900 to the L side cover member side (step S45).
Next, the storage medium 31, which is delivered in the step S45, is conveyed in the L side cover member (step S46).
Lastly, the storage medium 31, which is conveyed in the step S46, is inserted into a recording and reproduction apparatus (not illustrated) provided in the L side cover member (step S47).
According to the second type of extended library apparatus show in FIG. 21, as in the first type of extended library apparatus show in FIG. 19, there is no need to couple the rails to one another, and thus it is easy in establishment. However, in the event that the storage medium is mounted through the storage medium delivery mechanism on the drive, a time (hereinafter, this time is referred to as a conveyance time) from deriving the storage medium from the storage shelf up to mounting it on the drive requires a time on the order of two times to three times as much as the conveyance time in the first type of extended library apparatus show in FIG. 19. This involves a problem that efficiency in conveyance per hour becomes worse.
Further, according to the second type of extended library apparatus show in FIG. 21, there are provided the same number of moving mechanisms as the number of coupled library apparatuses. Thus, as compared with the first type of extended library apparatus show in FIG. 19, which is capable of coping with coupling of a plurality of library apparatuses with one moving mechanism, it involves problems of high cost and increment of dissipation power.